Measurements of the dispersion of magnetic excitons have been made in a single crystal of praseodymium metal using inelastic neutron scattering. A preliminary analysis of the data yields the first detailed information about the exchange interactions and the crystal field splittings in the light rare-earth metals.

• Received 5 April 1971

DOI:https://doi.org/10.1103/PhysRevLett.26.1254